The present invention relates generally to interface devices between humans and computers, and more particularly to computer input devices that provide force feedback to the user.
Computer systems are used extensively in the home entertainment industry to implement video games, video simulations, and the like. In the video game industry, a video game computer system displays a visual game environment to a user on a display screen or other visual output device. Users can interact with the displayed environment to play a game, experience a simulation or "virtual reality" environment, or otherwise influence events depicted on the screen. Such user interaction is implemented through the use of a human-computer interface device, such as a joystick, "joypad" button controller, mouse, stylus and tablet, or the like, that is connected to the computer system controlling the game environment.
One common interface device to game environments is a joystick controller. A joystick usually includes a member for the user to grasp and move in one or more degrees of freedom. The user's manipulations of the joystick are input to the computer system and the results or effects of these manipulations are typically displayed to the user on the display screen. While a standard joystick is effective in allowing a user to input commands to a game environment, it is limited, to providing only input to the game computer system. The user can receive feedback about the results of his or her actions only through the visual medium of the display screen and, usually, the auditory medium. A standard joystick cannot itself provide feedback information to the user. For example, if the simulated aircraft that the user is controlling in a game environment collides with another aircraft, the user only receives the visual and auditory feedback that such a collision occurred. The standard joystick has no means of conveying such collision information to the user.
Joysticks and other input devices have been developed to provide tactile ("haptic") feedback to a user, more generally known as "force feedback." These types of joysticks can provide physical sensations to the user manipulating the joystick. Typically, motors are coupled to the
Other concerns regarding force feedback joysticks include the efficiency of manufacturing and marketing the joysticks. The cost, complexity, reliability, and size of a force feedback joystick for home use should be practical enough to mass produce the devices. In addition, aesthetic concerns such as compactness and operating noise level of a force feedback device are of concern in the home market. Since the prior art feedback controllers are mainly addressed to specific applications in industry, most force feedback mechanisms are costly, large, heavy, have significant power requirements, are difficult to program for applications. The prior art devices require high speed control signals from a controlling computer for stability, which usually requires more expensive and complex electronics. In addition, the prior art force feedback devices are typically large and noisy. These factors provide many obstacles to the would-be manufacturer of force-feedback joysticks to the home video game market.
For example, the pneumatic force feedback device of Burdea et al. mentioned above includes many disadvantages to a would-be provider of force feedback devices in the home video game industry. The force feedback interface of Burdea et al. requires a large interface box including bulky pressure regulators, pressurized air supply, and a large 24-volt power supply. The active pneumatic actuators of Burdea et al. require high speed control signals to operate effectively and provide stability. Finally, Burdea et al's pneumatic actuators can potentially be dangerous for a user when strong or unexpected forces are generated on a user of the interface.
Therefore, a safer, less expensive, less complex, more compact, more reliable, easier programmed, more aesthetic alternative to force feedback interface devices is desired for certain applications. joystick and are connected to the controlling computer system. The computer system can provide forces on the joystick in conjunction with gaming events by controlling the motors. Through such a joystick, the computer system can convey to the user the physical sensation of colliding into a wall, moving through a liquid, driving over a bumpy road, and other sensations. The user can thus experience an entire sensory dimension in the gaming experience that was previously absent. Force feedback joysticks can provide a whole new modality for human-computer interaction.
Force feedback input devices of the prior art have concentrated on providing maximum haptic fidelity, i.e., the realism of the tactile feedback was desired to be optimized. This is because most of the force feedback devices have been targeted at the specific needs of highly industrial applications. To attain such realism, important design concerns such as size, weight, complexity, power consumption, programming compatibility, cost, aesthetics, and safety have been sacrificed. As a result, typical force feedback mechanisms are complex robotic mechanisms which require precision components, high speed interface electronics, and expensive actuators.
To provide realistic force feedback, the devices of the prior art typically use servo motors under computer control. Pneumatic and hydraulic devices are also used as actuators in force feedback devices. In pneumatic and hydraulic devices, a source of pressurized fluid is usually coupled to a piston in a cylinder, and the flow of the pressurized fluid is controlled by a computer system to provide active forces to the user. For example, a pneumatic system is described by Burdea et al. in U.S. Pat. No. 5,143,505, in which active pneumatic actuators are provided on an interface glove to provide force feedback to a user's fingers. These systems regulate pressurized air to generate active forces to the user.
While the potential market and applications of force feedback controllers in the home video game industry is immense, a number of concerns face the potential providers of force feedback joysticks to the general public for video game and similar applications. Foremost among these concerns is the issue of user safety. Because a force feedback device can impart physical forces upon the user, the potential for injury must be carefully addressed. One type of potential injury is an impact injury, which is caused by a driving blow to the user from the joystick handle. Equally as important are repetitive motion injuries, which are debilitative injuries that are caused by moderate jarring of the user's hand over an extended period of game play. Such injury issues must be resolved before force feedback joysticks can be practically sold to the general public.
In the prior art feedback controllers, active forces are directly applied to the user to provide an inherently unsafe controller. In addition, high accelerations are usually produced to provide a wide range of force signal frequencies and achieve the desired high realism. However, such accelerations are even more unsafe for a user operating the device. These joysticks and other devices are thus unfit for the home market of video games and the like.